Milton Marks III, a member of a noted San Francisco political family and a trustee of the City College of San Francisco, died at his San Francisco home Thursday. Mr. Marks was 52 and suffered from glioblastoma, an aggressive form of brain tumor.

Services will be held at the Sinai Memorial Chapel, 1501 Divisadero St., San Francisco, at 11:30 a.m. Sunday.

Mr. Marks suspected that his brain tumor was connected to heavy use of cellular phones, and spoke out often in support of requiring cell phone companies to disclose how much radiation is emitted by the devices.

It was the demands of a political campaign that convinced Mr. Marks to acquire and use a cell phone. He suffered a seizure in December 2010 and strongly suspected - but could never prove - that the tumor he developed was connected to his cell phone.

Mr. Marks had a career as an executive with nonprofit organizations, particularly Friends of the Urban Forest, which planted trees all over the city.

He was also devoted to the region's community colleges and first ran for the San Francisco Community College board in 2000 and was re-elected twice. In his last campaign in 2008, he set a record for the most votes received for the community college board.

He served as president of the City College board, as vice president and as chair of a number of important committees. He attended a trustee meeting as recently as last week and had been working on solutions to the college's problems with accreditation.

"He was dedicated to the needs and priorities of our students, education reform (and) environmental stewardship," said Mayor Ed Lee in a statement.

Lee also called Mr. Marks "a champion for our most vulnerable communities in San Francisco."